Lactoferrin prevents invasion and inflammatory response following E. coli strain LF82 infection in experimental model of Crohn's disease

BackgroundCrohn's disease is a multifactorial disease in which an aberrant immune response to commensal intestinal microbiota leads to chronic inflammation. The small intestine of patients with Crohn's disease is colonized by a group of adherent-invasive Escherichia coli strongly able to adhere and invade intestinal epithelial cells lactoferrin is an iron-binding glycoprotein known to have anti-bacterial and anti-inflammatory activities.AimsWe explore the ability of bovine lactoferrin to modulate the interactions between the adherent-invasive E. coli strain LF82 and intestinal epithelial cells as well as the inflammatory response.MethodsBacterial adhesion and invasion assays were used to assess the antimicrobial activity of lactoferrin. Electron microscopy was used to characterize bacteria–cell interactions. The mRNA expression of pro-inflammatory cytokines was measured both in cultured cells and in biopsies taken from intestine of patients affected by Crohn's disease.ResultsLactoferrin inhibited bacterial invasion through minimally affecting adhesion. This divergence was due to a mannose-dependent lactoferrin binding to the bacterial type 1 pili and consequent bacterial aggregation on the intestinal epithelial cell surface. Expression of pro-inflammatory cytokines, such as TNF-alpha, IL-8, and IL-6, was markedly inhibited by lactoferrin both in cultured and Crohn-derived intestinal cells.ConclusionsBovine lactoferrin might function via an antibacterial and/or anti-inflammatory mechanism in the treatment of Crohn's disease.